When the shield passes through the composite stratum, the content of water rich gravelly sand layer is high, which is prone to "gushing", tunnel face instability, and the content of argillaceous siltstone stratum is high, which is more prone to mud cake, tool locking, eccentric wear and slag discharge. In view of these construction problems above, the shield section of Qili station-Minyuan Road West Station of Nanchang Metro Line 4 as an example, which passes through the water rich gravel sand-argillaceous siltstone composite stratum, this paper conducts the soil conditioning tests for five tunnel faces with different composite degrees and examines the reasonable proportion of soil conditioning mixture ratio in these varying composite of earth pressure balance shield. The results show that:with the ratio increase of argillaceous siltstone from 10% to 90%, the foam injection ratio increases from 20% to 50%, and the injection ratio of bentonite slurry decreases from 20% to 0. The field application results show that the soil conditioning scheme above can ensure the good fluidity and low permeability of the muck, and solve the problems of gushing and mud cake during shield tunneling in different degrees of composite stratum.