To obtain accurate assessment results on the earthquake monitoring capability of Liaoning seismic network, analyze the spatial and temporal distribution characteristics of earthquake monitoring in Liaoning province and its neighboring regions, and provide scientific basis for seismic network optimization, the probability-based magnitude of completeness (PMC) method was first applied to the Liaoning seismic network. To investigate the seismic detection capability of 37 stations in Liaoning seismic network, this research selected the seismic observation report and station information from January 2010 to December 2017. The results show that the PMC method can objectively reflect the capability of stations to detect earthquake events. Stations around the old Yingkou-Haicheng seismic region exhibit higher detecting capability for earthquakes with smaller magnitudes. Given the network distribution, stations at the edge of Liaoning province present lower detecting capability. The spatiotemporal distribution characteristics of minimum PMC (M_P) demonstrate the following values:1.2 ≤ M_P ≤ 1.5 in Shenyang-Liaoyang-Benxi-Anshan-Panjin area of central Liaoning; M_P ≥ 3.0 in Dalian area of south Liaoning; and 2.5 ≥ M_P ≥ 1.8 in other areas of Liaoning. The study results indicate that to further strengthen the monitoring capability of Liaoning seismic network, more stations should be constructed in east and southeast Liaoning to increase station density. Furthermore, the introduction of Hebei-shared stations in west Liaoning can increase the detecting capability of the study area.