The invention discloses a fixed-point data screening circuit. The fixed-point data screening circuit comprises a rising edge detection circuit, an input circuit, a subtracter and an output circuit, wherein to-be-screened data A, address data B of the to-be-screened data in a memory and a threshold value DR0 during execution of a threshold value comparison instruction are used as input data; the data A is input into the minuend input end of the subtracter, the DR0 or the last piece of data A is input into the subtrahend end of the subtracter, and the output end of the subtracter is connected with the rising edge detection circuit; and the output end of the rising edge detection circuit and the output end of the input circuit are both connected with the output circuit. Through the fixed-point data screening circuit, a large amount of fixed-point data can be screened in a data stream mode, and data or corresponding addresses meeting designated conditions can be given. When the screening circuit is designed in an ALU, screening of fixed-point data can be quickly completed, design of a software program is simplified, execution energy consumption of a processor is lowered, and the defect that an ordinary data comparison instruction can only be used for comparing a small amount of data (generally two pieces of data) is overcome.