This research present the wave impart analysis on the operational safety of cargo ship in harbor and it effect on a mooring line system. From the analysis using MATLAB program the wave formed velocity in horizontal direction show a 1% decrease from (0.1 to 8m) of the water depth and the velocity in vertical direction show 2% increase from (0.1 to 8m) of the water depth. The acceleration in horizontal direction show 2% increase from (0.1 to 8m) of the water depth and the acceleration in vertical direction show 2% decrease with from (0.1 to 8m) of the water depth. The wave load on the mooring line between two anchors (A and B) of 1059m suspended length (Ls) is 200KN with horizontal restoring force at the Fairland (TH) of 1200KN which increase the tension by 250KN and causes the Fairland shift by 0.54m. This resulted to a reduction in mooring anchor XB to 498.96m and XA to 500.04m. The analysis also shows that the rate of water particle velocity and acceleration due to wave effects decrease with increase water depth, and the combined effect will cause damage to the catenary mooring line in extreme significant waves height and period. Sudden and critical tension on the chain and anchor A and B may set under this environmental load. The stability and dynamic positioning of any floating vessel is essential during offshore activities in the harbor. Therefore, it is necessary to carryout mooring system analysis and monitoring for safe ship operation under environmental wave load in the Harbor.