Abstract: Using heavy fog data from 8 meteorological observation stations (Shenyang, Liaozhong, Tai’an, Panjin, Jinzhou, Huludao, Xingcheng, Suizhong) in 1981-2012 along Shenshan highway, we analyzed the spatial and temporal pattern of heavy fog along Shenshan highway. Results showed that the heavy fog times increased in the past 10 years with 16.4 days per year on average, 1.8 days more compared with that of 1980s. Data of Liaozhong, Tai’an, Panjin and Shenyang stations indicated that the heavy fog weather appeared mainly at fall and winter, while in Jinzhou, Huludao, Xingcheng and Suizhong, the fog weather happened mainly in summer and fall. There were two peak times for heavy fog occurrences: one in 03-06 am, the other in 21-24 pm. The fog dissipation time was mainly before 15 pm, with peak time at 9 am. 89% of heavy fog only lasted less than 10 hours, with most lasting for 2-4 hours. Southwestern section of the Shenshan highway along sea had more fog days, while inland section had few fog days, with distinctive regional differences. Based on the analysis of traffic accidents caused by heavy fog from 2008 to 2012, we discussed the impact of heavy fog on transportation, selected key hidden trouble spot, and proposed suggestions on the prevention of heavy fog.