The invention discloses a multi-manufacturer interlocking control system for rail transit, including a plurality of interlocking machines and a relay combination cabinet, and also a conversion device connecting the two. The conversion device includes a plurality of interlocking conversion units, communication switching units and relay conversion units in sequence, and the interlocking conversion units are one-to-one corresponding to the interlocking machines and their input ends are connected with the corresponding interlocking machines for communication. The interlocking conversion unit is used to convert the electrical signal of the interlocking machine into a CAN signal and transmit it to the communication switching device. The communication switching device is a single device and is communicatively connected to each interlocking conversion unit. The communication switching device obtains the CAN signal reported by the interlocking conversion unit and converts it into a digital signal to send to the relay conversion unit. The relay conversion unit is used to convert the digital signal into an electric signal and control the operation of the relays in the relay combination cabinet.