In this study, the method of Fault Movement Potential (FMP) proposed by Lee et al. (1997) is used to assess the movement potential of some major faults and its relationship with the seismic activities in Northwestern Vietnam. The fault movement potential is assessed by the magnitude of FMP (from 0 to 1) and calculated based on the relationship between kinematic characteristics of the faults and regional tectonic stress field. The maximum compressive stress axis in Northwestern Vietnam has the nearly horizontal trend (7.4±4.0) and the direction of 170.2±6.7. The calculated results of FMP at 60 geological survey points along major faults in Northwestern Vietnam show that the movement potential of these faults is mainly from medium to high (40/60 points with FMP = 0.6 - 0.9). In particular, the faults in Dien Bien Phu have the highest movement potential (FMP = 0.8 - 0.9). An earthquake catalog that consists of 177 earthquakes with M = 4.0 - 6.8 occurring in the studied area from 1277 to 2016 is used to assess the relationship between seismic activities and fault movement potential. The research results indicate that at the locations on the faults with high movement potential, seismic activities occur frequently. On the segment of Son La fault zone in Tuan Giao, Tua Chua, the movement potential has the highest value (FMP = 0.9), corresponding to the occurrence of Tuan Giao earthquake with M = 6.8 in 1983. On the contrary, weak earthquake or even no earthquake occur at the locations with low movement potential such as the segment of Son La fault in Moc Chau, Yen Chau, the segment of Ma River fault in Lang Chanh and the Than Uyen fault in Than Uyen. With the complete survey dataset on slip surface attitude of faults in contemporary times, FMP is significant for assessing the level of seismic activities on each part of the faults, serving the segmentation of faults, establishment of seismogenic regions, earthquake prediction and seismic hazard assessment.