Abstract: Determining ²⁵²Cf neutron source strength plays a practical significance in fields of nuclear technology and applications. Based on the multiplicity distribution and the decay action of ²⁵²Cf spontaneous fission neutrons, an alternative method was studied to measure the neutron source strength. This method could provide the neutron strength for the measured samples without any additional knowledge. Five ²⁵²Cf neutron sources were placed in a neutron multiplicity counter for a longtime measurement, and the largest assay neutron strength relative deviation is 1.41%, which verifies the validity of this method preliminarily.