A method and an apparatus for generating a source-independent quantum random number are disclosed. The method includes: receiving by a receiver a photon signal sent by a source and converting by the receiver a multi-photon signal contained in the photon signal into a single-photon signal equivalent to the multi-photon signal; modulating a single-photon signal in an X basis or a Z basis, and performing a projection measurement on the X basis or the Z basis randomly; calculating an error rate of the source according to a measurement result of the Z basis; obtaining a partially random binary string according to a measurement result of the X basis; and obtaining and processing a minimal entropy of the partially random binary string so as to obtain a completely random binary string.