The invention discloses a railway three-phase signal power supply voltage/current acquisition circuit which comprises a multi-way simulation switch circuit, an amplification circuit, a filtering circuit, an A/D conversion circuit and a microprocessor which are connected in sequence, wherein an A-phase voltage isolation sampling circuit, a B-phase voltage isolation sampling circuit, a C-phase voltage isolation sampling circuit, an A-phase current isolation sampling circuit, a B-phase current isolation sampling circuit and a C-phase current isolation sampling circuit are connected with the input end of the multi-way simulation switch circuit; the A-phase voltage isolation sampling circuit, the B-phase voltage isolation sampling circuit and the C-phase voltage isolation sampling circuit all consist of electronic transformers T, diodes D1 and diodes D2; the A-phase current isolation sampling circuit, the B-phase current isolation sampling circuit and the C-phase current isolation sampling circuit all consist of current transformers CT, diodes D3 and diode D4. The railway three-phase signal power supply voltage/current acquisition circuit is reasonable in design, high in voltage and current acquisition precision, high in anti-interference property and high in working reliability, and electric isolation is achieved.