The invention discloses a shale transformation volume quick judging method based on microseism, which is characterized in that the method comprises the following steps: S1, aiming at a plurality of wells which have been monitored by micro-seismic field, establishing three calculation models of reconstruction volume according to field fracturing operation curves and micro-seismic characteristics; S2, calculating the effective liquid quantity on the basis of three modified volume calculation models; S3, simulating the relation diagram between different effective liquid quantity and fracture length by the discrete fracture network simulation method, that is, calculating the fracture parameters by the effective liquid quantity, and predicting the reconstruction volume in real time by the fracture parameters; S4, combined with the three models, establishing a typical control chart of effective liquid volume, typical curve, seam length and modified volume. The method realizes the real-time pre-judgement of the transformation volume through the field operation curve characteristics, and provides the corresponding fracturing design optimization adjustment direction for the completed well,the well under construction and the deployment well with similar geological conditions in the later period. The method effectively solves the problems of post-fracturing effect evaluation and fracturing operation parameter optimization.