The invention discloses a method for preventing earthquake liquefaction instability of an ultrafine tailing heaping upstream method tailing dam. An initial dam (5) and a dam abutment flood stop ditch (1) are built according to a design scheme; embedment depths of a first earthquake liquefaction resisting medium-coarse sand drainage/seepage layer and a second earthquake liquefaction resisting medium-coarse sand drainage/seepage layer are determined according to the region seismic fortification intensity; the first and second earthquake liquefaction resisting medium-coarse sand drainage/seepage layers both consist of medium-coarse sand drainage/seepage layers (11), and a row of groove hole drainage/seepage pipes (3) paved in the medium-coarse sand drainage/seepage layers (11); the groove hole drainage/seepage pipes (3) are communicated with drainage communicating pipes (2) through three-way pipes (12); and the outer ends of the drainage communicating pipes (2) are connected with the dam abutment flood stop ditch (1). The method improves the earthquake liquefaction resistance and the stability of the ultrafine tailing heaping dam, prevents the earthquake liquefaction instability damage, and in particular, is suitable for the ultrafine tailing heaping upstream method tailing dam in high-intensity earthquake region.