The invention provides a configurable convolutional neural network processor circuit, which comprises an FIR filtering module, a windowing processing module and a neural network operation module, wherein the neural network operation module comprises a convolution layer, a pooling layer, a configurable activation function layer and a full connection layer; and the configurable activation function layer comprises an absolute value setting module, an interval judgment module, a first multiplexer, a configuration module, an address generation module, an RAM, an interval expansion module and a second multiplexer. The configurable activation function layer is configured with a sigmoid function or a tanh function and errors, so that the universality and the flexibility of the processor are greatly improved; by combining hierarchical quantization and saturation truncation, the quantization standard of each layer of neural network is configurable, and the overflow risk is reduced; and an FIR filtering function is realized by multiplexing a multiply-accumulate-add operation unit of a full connection layer, and data is transmitted by adopting a two-stage data transmission mode, so that the power consumption is further reduced.