The invention discloses a method of a microprocessor asynchronously reading peripheral equipment FIFO length; the method comprises the following steps: 1, outputting a reading signal: outputting a group of FIFO length reading bus signal accessing the peripheral equipment when the microprocessor is needed to read the peripheral equipment chip FIFO length; 2, determining whether the present FIFO length is valid or not: the microprocessor can at most read the peripheral equipment chip FIFO length for 3 times according to the FIFO length reading bus signals, and the length values of each time are cached so as to determine whether the length value is valid or not; 3, determining the final FIFO length: obtaining the final around value of the peripheral equipment chip FIFO length once the FIFO length is determined to be valid. The novel method can solve the reading errors caused by unstability when the microprocessor asynchronously reads the peripheral equipment chip FIFO length.