趙桓(宋(song)(song)(song)(song)欽宗(zong)(zong)(zong))即(ji)位后(hou)(hou),升李(li)(li)(li)綱(gang)(gang)(gang)(gang)為(wei)(wei)尚書(shu)右丞,就任(ren)(ren)親征行營(ying)使(shi)(shi),負責(ze)開封(feng)的(de)(de)防(fang)御。李(li)(li)(li)綱(gang)(gang)(gang)(gang)率領開封(feng)軍(jun)(jun)民及(ji)(ji)時完(wan)(wan)成防(fang)御部(bu)署,親自登城(cheng)督戰(zhan),擊退金(jin)(jin)兵(bing)。金(jin)(jin)帥完(wan)(wan)顏(yan)宗(zong)(zong)(zong)望見開封(feng)難以(yi)強(qiang)(qiang)攻,轉而施行誘降(jiang)之(zhi)計(ji),宋(song)(song)(song)(song)廷(ting)(ting)(ting)彌漫了屈辱投降(jiang)的(de)(de)氣氛。李(li)(li)(li)綱(gang)(gang)(gang)(gang)因(yin)堅決反對向金(jin)(jin)割地求(qiu)和,被(bei)(bei)宋(song)(song)(song)(song)欽宗(zong)(zong)(zong)罷(ba)(ba)官。由(you)于(yu)(yu)(yu)開封(feng)軍(jun)(jun)民憤怒示威(wei),迫(po)使(shi)(shi)宋(song)(song)(song)(song)欽宗(zong)(zong)(zong)收回(hui)成命,李(li)(li)(li)綱(gang)(gang)(gang)(gang)才(cai)又被(bei)(bei)起用。完(wan)(wan)顏(yan)宗(zong)(zong)(zong)望因(yin)無(wu)力攻破(po)開封(feng),在宋(song)(song)(song)(song)廷(ting)(ting)(ting)答應割讓(rang)河北三鎮之(zhi)后(hou)(hou),遂于(yu)(yu)(yu)靖康元(yuan)年(nian)(nian)(nian)(nian)(1126年(nian)(nian)(nian)(nian))二月(yue)(yue)(yue)撤(che)兵(bing)。開封(feng)守衛戰(zhan)在李(li)(li)(li)綱(gang)(gang)(gang)(gang)組織(zhi)下(xia)獲得(de)勝利。金(jin)(jin)兵(bing)撤(che)離之(zhi)后(hou)(hou),李(li)(li)(li)綱(gang)(gang)(gang)(gang)即(ji)遭到(dao)宋(song)(song)(song)(song)廷(ting)(ting)(ting)投降(jiang)派(pai)的(de)(de)排斥和誣陷。靖康元(yuan)年(nian)(nian)(nian)(nian)(1126年(nian)(nian)(nian)(nian))五月(yue)(yue)(yue),宋(song)(song)(song)(song)廷(ting)(ting)(ting)強(qiang)(qiang)令(ling)李(li)(li)(li)綱(gang)(gang)(gang)(gang)出任(ren)(ren)河東、河北宣撫使(shi)(shi),驅(qu)(qu)趕他(ta)出朝(chao)。李(li)(li)(li)綱(gang)(gang)(gang)(gang)就任(ren)(ren)后(hou)(hou),宋(song)(song)(song)(song)廷(ting)(ting)(ting)又事(shi)事(shi)加以(yi)限(xian)制(zhi),使(shi)(shi)宣撫使(shi)(shi)徒具(ju)空名(ming),無(wu)節制(zhi)軍(jun)(jun)隊之(zhi)權。李(li)(li)(li)綱(gang)(gang)(gang)(gang)被(bei)(bei)迫(po)于(yu)(yu)(yu)靖康元(yuan)年(nian)(nian)(nian)(nian)(1126年(nian)(nian)(nian)(nian))九月(yue)(yue)(yue)辭職,旋又被(bei)(bei)加上“專主戰(zhan)議,喪師費財”的(de)(de)罪名(ming),先(xian)責(ze)建昌軍(jun)(jun)(今江西南(nan)城(cheng))安置(zhi),再謫夔州(zhou)(今重慶奉(feng)節白帝城(cheng))。李(li)(li)(li)綱(gang)(gang)(gang)(gang)被(bei)(bei)貶不久,金(jin)(jin)兵(bing)再次兩路南(nan)下(xia)圍(wei)攻開封(feng)。宋(song)(song)(song)(song)欽宗(zong)(zong)(zong)在被(bei)(bei)俘前夕又想(xiang)起用李(li)(li)(li)綱(gang)(gang)(gang)(gang),任(ren)(ren)命他(ta)為(wei)(wei)資(zi)政殿大學(xue)士、領開封(feng)府事(shi),但(dan)已無(wu)濟于(yu)(yu)(yu)事(shi)。南(nan)宋(song)(song)(song)(song)建立后(hou)(hou),他(ta)主張(zhang)堅決抗(kang)金(jin)(jin)及(ji)(ji)反對投降(jiang)活動,卻(que)為(wei)(wei)宋(song)(song)(song)(song)高(gao)宗(zong)(zong)(zong)及(ji)(ji)汪(wang)伯(bo)彥、黃潛善所(suo)不容。因(yin)此,他(ta)們又設法驅(qu)(qu)逐(zhu)李(li)(li)(li)綱(gang)(gang)(gang)(gang)。首先(xian),調李(li)(li)(li)綱(gang)(gang)(gang)(gang)任(ren)(ren)尚書(shu)左(zuo)(zuo)仆射(she)兼(jian)門下(xia)侍郎(lang)(lang)(左(zuo)(zuo)相(xiang)(xiang)),另委黃潛善接(jie)任(ren)(ren)右仆射(she)兼(jian)中書(shu)侍郎(lang)(lang),以(yi)牽制(zhi)李(li)(li)(li)綱(gang)(gang)(gang)(gang)。接(jie)著,又罷(ba)(ba)免張(zhang)所(suo)、傅亮(liang),撤(che)銷(xiao)河北招撫司及(ji)(ji)河東經(jing)制(zhi)司,蓄意破(po)壞李(li)(li)(li)綱(gang)(gang)(gang)(gang)的(de)(de)抗(kang)金(jin)(jin)部(bu)署,迫(po)使(shi)(shi)李(li)(li)(li)綱(gang)(gang)(gang)(gang)辭職。李(li)(li)(li)綱(gang)(gang)(gang)(gang)主政僅(jin)七(qi)十(shi)五天,建炎元(yuan)年(nian)(nian)(nian)(nian)(1127年(nian)(nian)(nian)(nian))八月(yue)(yue)(yue)十(shi)八日便遭罷(ba)(ba)相(xiang)(xiang),為(wei)(wei)觀文殿大學(xue)士,提舉杭州(zhou)洞霄宮。一生為(wei)(wei)國,卻(que)不得(de)愿。