趙桓(huan)(宋(song)(song)(song)(song)欽宗(zong))即(ji)位后,升李(li)(li)(li)綱(gang)(gang)(gang)為(wei)(wei)尚書右(you)(you)丞,就(jiu)任(ren)親征(zheng)行營使(shi),負(fu)責開(kai)(kai)(kai)封(feng)(feng)(feng)的防御。李(li)(li)(li)綱(gang)(gang)(gang)率領開(kai)(kai)(kai)封(feng)(feng)(feng)軍(jun)民(min)及時(shi)完(wan)成(cheng)防御部署,親自(zi)登城督戰(zhan),擊退金兵(bing)(bing)。金帥完(wan)顏宗(zong)望見(jian)開(kai)(kai)(kai)封(feng)(feng)(feng)難以強攻,轉而(er)施行誘降之計,宋(song)(song)(song)(song)廷彌漫了屈辱投(tou)降的氣氛(fen)。李(li)(li)(li)綱(gang)(gang)(gang)因(yin)(yin)堅(jian)決(jue)反對(dui)向金割地求和(he),被(bei)(bei)宋(song)(song)(song)(song)欽宗(zong)罷(ba)官。由于開(kai)(kai)(kai)封(feng)(feng)(feng)軍(jun)民(min)憤怒示威(wei),迫(po)使(shi)宋(song)(song)(song)(song)欽宗(zong)收回(hui)成(cheng)命,李(li)(li)(li)綱(gang)(gang)(gang)才又(you)(you)被(bei)(bei)起(qi)用。完(wan)顏宗(zong)望因(yin)(yin)無力攻破開(kai)(kai)(kai)封(feng)(feng)(feng),在宋(song)(song)(song)(song)廷答應割讓河(he)北三鎮之后,遂于靖康元年(nian)(1126年(nian))二月撤(che)兵(bing)(bing)。開(kai)(kai)(kai)封(feng)(feng)(feng)守衛(wei)戰(zhan)在李(li)(li)(li)綱(gang)(gang)(gang)組(zu)織(zhi)下(xia)獲得勝利。金兵(bing)(bing)撤(che)離之后,李(li)(li)(li)綱(gang)(gang)(gang)即(ji)遭到宋(song)(song)(song)(song)廷投(tou)降派的排斥和(he)誣陷(xian)。靖康元年(nian)(1126年(nian))五月,宋(song)(song)(song)(song)廷強令李(li)(li)(li)綱(gang)(gang)(gang)出(chu)任(ren)河(he)東(dong)、河(he)北宣撫使(shi),驅趕他(ta)(ta)出(chu)朝(chao)。李(li)(li)(li)綱(gang)(gang)(gang)就(jiu)任(ren)后,宋(song)(song)(song)(song)廷又(you)(you)事事加以限(xian)制(zhi)(zhi),使(shi)宣撫使(shi)徒具(ju)空名,無節(jie)制(zhi)(zhi)軍(jun)隊之權。李(li)(li)(li)綱(gang)(gang)(gang)被(bei)(bei)迫(po)于靖康元年(nian)(1126年(nian))九月辭(ci)職,旋又(you)(you)被(bei)(bei)加上(shang)“專主(zhu)戰(zhan)議,喪師費財”的罪名,先(xian)責建(jian)(jian)昌軍(jun)(今江西南城)安置,再謫夔州(今重慶奉節(jie)白帝城)。李(li)(li)(li)綱(gang)(gang)(gang)被(bei)(bei)貶不(bu)(bu)久,金兵(bing)(bing)再次兩路南下(xia)圍攻開(kai)(kai)(kai)封(feng)(feng)(feng)。宋(song)(song)(song)(song)欽宗(zong)在被(bei)(bei)俘前(qian)夕又(you)(you)想起(qi)用李(li)(li)(li)綱(gang)(gang)(gang),任(ren)命他(ta)(ta)為(wei)(wei)資政殿大學士(shi)、領開(kai)(kai)(kai)封(feng)(feng)(feng)府(fu)事,但已(yi)無濟于事。南宋(song)(song)(song)(song)建(jian)(jian)立后,他(ta)(ta)主(zhu)張(zhang)堅(jian)決(jue)抗金及反對(dui)投(tou)降活動,卻為(wei)(wei)宋(song)(song)(song)(song)高宗(zong)及汪伯彥(yan)、黃潛善所(suo)(suo)不(bu)(bu)容。因(yin)(yin)此,他(ta)(ta)們(men)又(you)(you)設法驅逐李(li)(li)(li)綱(gang)(gang)(gang)。首(shou)先(xian),調(diao)李(li)(li)(li)綱(gang)(gang)(gang)任(ren)尚書左仆射(she)兼門下(xia)侍郎(左相),另(ling)委黃潛善接任(ren)右(you)(you)仆射(she)兼中(zhong)書侍郎,以牽制(zhi)(zhi)李(li)(li)(li)綱(gang)(gang)(gang)。接著,又(you)(you)罷(ba)免張(zhang)所(suo)(suo)、傅亮,撤(che)銷河(he)北招撫司及河(he)東(dong)經制(zhi)(zhi)司,蓄意破壞李(li)(li)(li)綱(gang)(gang)(gang)的抗金部署,迫(po)使(shi)李(li)(li)(li)綱(gang)(gang)(gang)辭(ci)職。李(li)(li)(li)綱(gang)(gang)(gang)主(zhu)政僅七十五天,建(jian)(jian)炎元年(nian)(1127年(nian))八(ba)月十八(ba)日便遭罷(ba)相,為(wei)(wei)觀(guan)文殿大學士(shi),提舉(ju)杭州洞霄宮。一生為(wei)(wei)國,卻不(bu)(bu)得愿。