趙桓(宋(song)(song)欽宗(zong)(zong))即(ji)位后,升李(li)(li)(li)綱(gang)(gang)(gang)為尚書(shu)右丞,就(jiu)任(ren)親征行營使(shi),負責開(kai)封(feng)(feng)的(de)(de)(de)防(fang)御。李(li)(li)(li)綱(gang)(gang)(gang)率領開(kai)封(feng)(feng)軍(jun)民及(ji)時完(wan)成防(fang)御部署,親自登城督戰,擊退金(jin)兵。金(jin)帥完(wan)顏(yan)宗(zong)(zong)望見開(kai)封(feng)(feng)難以(yi)強攻(gong),轉而(er)施(shi)行誘降之(zhi)計,宋(song)(song)廷(ting)(ting)彌漫了(le)屈(qu)辱投降的(de)(de)(de)氣氛。李(li)(li)(li)綱(gang)(gang)(gang)因堅決反對(dui)向金(jin)割地求和,被(bei)宋(song)(song)欽宗(zong)(zong)罷官。由于開(kai)封(feng)(feng)軍(jun)民憤怒示威,迫使(shi)宋(song)(song)欽宗(zong)(zong)收回成命,李(li)(li)(li)綱(gang)(gang)(gang)才又(you)被(bei)起用(yong)。完(wan)顏(yan)宗(zong)(zong)望因無力攻(gong)破(po)開(kai)封(feng)(feng),在(zai)宋(song)(song)廷(ting)(ting)答應(ying)割讓(rang)河(he)北三鎮之(zhi)后,遂(sui)于靖康元年(1126年)二月撤兵。開(kai)封(feng)(feng)守(shou)衛戰在(zai)李(li)(li)(li)綱(gang)(gang)(gang)組(zu)織下(xia)獲得(de)勝利。金(jin)兵撤離(li)之(zhi)后,李(li)(li)(li)綱(gang)(gang)(gang)即(ji)遭到(dao)宋(song)(song)廷(ting)(ting)投降派的(de)(de)(de)排斥和誣陷。靖康元年(1126年)五(wu)月,宋(song)(song)廷(ting)(ting)強令李(li)(li)(li)綱(gang)(gang)(gang)出(chu)任(ren)河(he)東(dong)、河(he)北宣(xuan)撫使(shi),驅趕(gan)他(ta)出(chu)朝。李(li)(li)(li)綱(gang)(gang)(gang)就(jiu)任(ren)后,宋(song)(song)廷(ting)(ting)又(you)事事加(jia)(jia)以(yi)限制(zhi),使(shi)宣(xuan)撫使(shi)徒具空名(ming),無節制(zhi)軍(jun)隊之(zhi)權(quan)。李(li)(li)(li)綱(gang)(gang)(gang)被(bei)迫于靖康元年(1126年)九月辭職(zhi),旋又(you)被(bei)加(jia)(jia)上“專主(zhu)戰議,喪師費財”的(de)(de)(de)罪名(ming),先(xian)責建昌軍(jun)(今(jin)江西(xi)南(nan)城)安置,再謫夔州(今(jin)重慶奉節白(bai)帝(di)城)。李(li)(li)(li)綱(gang)(gang)(gang)被(bei)貶不(bu)久(jiu),金(jin)兵再次(ci)兩路南(nan)下(xia)圍(wei)攻(gong)開(kai)封(feng)(feng)。宋(song)(song)欽宗(zong)(zong)在(zai)被(bei)俘前夕(xi)又(you)想起用(yong)李(li)(li)(li)綱(gang)(gang)(gang),任(ren)命他(ta)為資政殿大學(xue)士、領開(kai)封(feng)(feng)府事,但已無濟(ji)于事。南(nan)宋(song)(song)建立后,他(ta)主(zhu)張堅決抗金(jin)及(ji)反對(dui)投降活(huo)動,卻為宋(song)(song)高宗(zong)(zong)及(ji)汪伯彥、黃(huang)潛(qian)善(shan)所(suo)不(bu)容。因此,他(ta)們又(you)設法驅逐(zhu)李(li)(li)(li)綱(gang)(gang)(gang)。首先(xian),調李(li)(li)(li)綱(gang)(gang)(gang)任(ren)尚書(shu)左仆(pu)射兼門下(xia)侍郎(左相),另(ling)委黃(huang)潛(qian)善(shan)接任(ren)右仆(pu)射兼中(zhong)書(shu)侍郎,以(yi)牽制(zhi)李(li)(li)(li)綱(gang)(gang)(gang)。接著,又(you)罷免(mian)張所(suo)、傅亮(liang),撤銷河(he)北招撫司及(ji)河(he)東(dong)經(jing)制(zhi)司,蓄(xu)意破(po)壞李(li)(li)(li)綱(gang)(gang)(gang)的(de)(de)(de)抗金(jin)部署,迫使(shi)李(li)(li)(li)綱(gang)(gang)(gang)辭職(zhi)。李(li)(li)(li)綱(gang)(gang)(gang)主(zhu)政僅七十五(wu)天,建炎元年(1127年)八月十八日便遭罷相,為觀文殿大學(xue)士,提(ti)舉杭州洞霄宮。一生(sheng)為國,卻不(bu)得(de)愿。