In this paper,the focal depth is calculated by the incident angle,sPL-Pg(etc),respectively in different epicentral distances,and by the simplex algorithm with the waves which are recorded by Liaoning Digital Seismic Network. The result shows that the focal depth should be about 14km,slightly deeper than 10km which is provided by the catalogue. The result is also suggested by SC/SOA and QH/HUY's waves,both being the distance seismic stations for the Dengta earthquake. The focal depths of earthquakes larger than M_L5.0 in Liaoning Province since 1970 follow a statistical pattern in distribution:deeper in eastern and western sides,shallower in middle zone,the southern of middle zone are shallower and the northern are deeper. The focal depth of the Dengta earthquake is consistent with this statistical pattern. This statistical pattern is of guiding significance to judge the disaster and to carry out emergency work.