A Ms6.4 earthquake occurred at Linkou country, Heilongjiang Province(44.8N, 129.9E) on January 2,2016 at a depth of 580 km. Pre-seismic gravity anomalies obtained at a 1 Hz sampling rate from Crustal Movement Observation Network of China(CMONOC) are analyzed after the earthquake. The results show that:(1) different from previous studies, both pre-seismic amplitude perturbation and co-seismic amplitude perturbation are not critical inversely proportional to epicentral distance;(2) unlike shallow earthquake, the pre-seismic and co-seismic amplitude perturbation of gravity illustrate synchronous spatial variation characters with decrease of epicentral distance for Linkou earthquake. This may because Linkou earthquake is a deep earthquake and occurred in Pacific Plate subduction zone;(3)compared to basement and semi-basement, cave can provide a better observation environment for g Phone gravimeter to detect pre-seismic gravity anomalies. A Ms6.4 occurred occurred at Linkou country, Heilongjiang Province (44.8N, 129.9E) on January 2,2016 at a depth of 580 km. Pre-seismic gravity anomalies obtained at 1 Hz sampling rate from Crustal Movement Observation Network of China (1) different from previous studies, both both pre-seismic amplitude perturbation and co-seismic amplitude perturbation are not critical inversely proportional to epicentral distance; (2) unlike shallow earthquake, the pre-seismic and co-seismic amplitude perturbation of gravity synchronous spatial variation characters with decrease of epicentral distance for Linkou earthquake. This may because Linkou earthquake is a deep earthquake and occurred in Pacific Plate subduction zone; (3) compared to basement and semi-basement, cave can provide a better observation environment for g Phone gravimeter to detect pre-seismic gravity anomalies.