A method for setting a calibration block for phased-array ultrasonic testing of a bimetal composite material includes the specific steps of firstly, partitioning a filling region groove type of the calibration block; secondly, setting testing reflectors at different positions on the filling region groove surfaces; thirdly, determining central coordinates on weld joint central lines of first, second, third and fourth upstream filling region reflectors; fourthly, determining central coordinates on a weld joint central line of an upstream hot weld region reflector; fifthly, setting two kinds of root groove region reflectors; sixthly, setting multiple kinds of creeping wave channel reflectors; seventhly, setting time-difference diffraction calibration reflectors; eighthly, setting a channel gate positioning reflector; ninthly, setting two kinds of volume channel reflectors; tenthly, symmetrically setting downstream reflectors. The method has the advantages that the requirements on testing of submarine pipelines made of the bimetal composite material are met, the problem that different types of defects at different positions are tested by a calibrated phased-array system, and reliability and onsite testing efficiency of the whole phased-array system are improved.