Aiming at the blind separation problem of non-cooperative receiving PCMA signals, Improved Particle Filtering based on Genetic Algorithm (GA-IPF) is proposed. Based on the particle filter algorithm framework, the algorithm establishes multiple state distributions to approximate the true posterior probability density. At the same time, genetic algorithm is introduced instead of resampling to generate new particles, which increases particle diversity and avoids particle depletion during resampling. Simulation results show that when the carrier-to-noise ratio is greater than 9 dB, the separation accuracy is over 95%, compared with QRD-M Gibbs and other algorithms, the signal acquisition capability of the algorithm is improved by 4 dB, and the algorithm complexity is reduced by nearly 60%.