The invention discloses an optical fiber current sensor and a collecting device, wherein the optical fiber current sensor comprises a signal input port, a signal processor, a first optical fiber signal output port, a second optical fiber signal output port and an optical fiber signal input port, wherein the signal input port is connected with the signal processor and is used for obtaining an inputsignal; the signal processor is respectively connected with the first optical fiber signal output port and the second optical fiber signal output port, and is used for outputting an optical fiber signal through the first optical fiber signal output port and the second optical fiber signal output port after the input signal is subjected to signal processing; the optical fiber signal input port isconnected with the signal processor, and is used for obtaining the input optical fiber signal; and the signal processor is also used for performing signal processing on the input optical fiber signal.The optical fiber current sensor provided by the invention can meet the requirements of miniaturization, integration, digitization and precision of primary and secondary fusion in a power distribution network.