Based on the observation and analysis of the vertical and horizontal component of gravitation on Hongshan station

and compared it with tidal component δ and γ of elasticity modulus in rock

we concluded that there are some anomlous variation of gravitational component and elastical parameters before several moderate earthquakes by using high precision instrument. The results show that there are two to six months anomaly of gravitational component before several moderate earthquakes which are less than 200 km from the observation station

the anomalous amplitude of vertical component is about 60～150 × 10-8ms-2

the anomalous variation of δ factor is about 2% and γ factor is 39%. The observational results correspond with conclusion of theoretic calculation

therefore we think that the observation of gravitational component has good future in earthquake monitor and prediction.