Using the 16 months' mooring data measured from September 2012 to December 2013 and the AVISO sea level anomaly data (SLA), we study the hydrological characteristics of mesoscale eddy and the deepwater circulation variations east of Indochina Peninsula. During the observation period, three mesoscale eddies are captured. Maximum amplitude of thermocline depth displacements, which are induced by local mesoscale eddies, on the mooring site can reach up to 50 m. The main conclusions are as follows. 1) In the mooring region, the time series correlation between temperature anomaly and the SLA weakens with the depth. 2) In the mooring region, mesoscale eddies affect the upper and intermediate hydrological conditions significantly. Deepwater circulation at 1 500 m and 2 000 m is primarily characterized by seasonal variations. Strong warm mesoscale eddies can influence deepwater circulation at 1 500 m depth, in the meanwhile, the deepwater velocity has strong 30-day periodical oscillations. However, the deepwater circulation at 2 000 m is not influenced by mesoscale eddies. 3) In the mooring region, the monthly mean velocity of deepwater circulation at 1 500 m in summer is larger than that in winter, the monthly mean velocity is up to 3.5 cm·s-1. Strong velocity of the deepwater circulation at 2 000 m depth appears in winter, the monthly mean velocity is up to 2.6 cm·s-1. The tide significantly influences the deepwater circulation, and the influences can reach 2 000 m depth and mainly on zonal direction.