A read circuit of storage class memory comprises: an array; a read reference circuit, having the same bit line parasitic parameters as the array, having the same read transmission gate parasitic parameters as the array, used to generate a read reference current; a sense amplifier, providing the same current mirror parasitic parameters as the reference side, used to generate a read current from a selected memory cell, compare the said read current with the said read reference current and output a readout result. In the present invention, the said read current and the said read reference current are generated at the same time, the transient curve of the said read reference current is between the low resistance state read current and the high resistance state read current from an early stage. The present invention largely reduces the read access time, has a good process variation tolerance, has a wide application, and is easy to be used in the practical product.