Abstract: According to the serious foor heave and dfficult prevention and control of the large crss section gob-side entry retaining in the deep mine,based on thegeological condtions of No.115(1) coal mining face in Gucia Mine as the engineering backgound aFLAC-numercal sirulation sofiware was appied to study thesectional foor heave featues of thelarge cross secion gob-side entr retaining in the dep mine.The studyresutis showed tht from the intital drving to the abandoned,he foor heave of thegateway retained was serious A serious foor heave was ocurred in the gateway driving stage. At the primary mining stage.the foor deformaton was coninuously increased.At the secondary mining stage .the foo defomation was more serious. The total foor heave value was over 1 @ m.Among the gataway drving ,rimary mining and secndary mining stages,the for heave value indiduallyreached the 21%,32% and 47 % of the total heavevalue.Uunder the infuencesof the prmary mining.the foor heave of th gatevay was serous from 30 m in front of thecoal mining face to 60 m at the rear of the coal mining face and those areas shoul be the key areas t prevent and control the foor heave. The study resuts could provde the guidance to prevent and control the foor heave of the large cross se:tion gob-side entry retaining in the deep mine.