The invention provides a multifunctional artificial core preparation instrument at least comprising a compact model cylinder and a high-temperature high-pressure pump communicated with the compact model cylinder, wherein the compact model cylinder is arranged in a constant-temperature box. The compact model cylinder comprises a cavity A, a cavity B, a connecting block, a pressing rod, a pressing cap A, a pressing cap B and two pistons, wherein the cavity A and the cavity B are connected through the connecting block, a through hole is formed at the center of the connecting block, the side face of the connecting block is provided with an air inlet hole and an air outlet hole which are communicated with the cavity B, the air inlet hole is communicated with an air compressor, the pressing rod penetrates through the through hole of the connecting block, the two ends of the pressing rod are connected with the two pistons respectively, the cavity A is sealed through the pressing cap A which is installed at the end of the cavity A and provided with a liquid outlet hole, and the cavity B is sealed through the pressing cap B which is installed at the end of the cavity B and provided with an oil inlet hole and an oil outlet hole. According to the multifunctional artificial core preparation instrument, the compaction pressure can reach 150 MPa, the work temperature can reach 150 DEG C, the multifunctional artificial core preparation instrument can continuously work for over 120 h at the temperature of 120-150 DEG C, and the warm-pressing system of a stratum under the real condition can be simulated.