Yellowfin tuna, Thunnus albacares, is a species of tuna found in the eastern Pacific Ocean, and has been one of the main targets of purse seine and longline fisheries since the 1970s. Chinese longline tuna fleets started to capture this species in 1999. According to the catch statistics from the Food and Agriculture Organization of the United Nations (FAO), during the period between 2008 and 2012, the annual catch of T. albacares ranged from 185 000 t to 260 000 t with an average of 213 000 t. The formation of T. albacares fishing grounds is considered to be complicated, and may be affected by many environmental factors. Many methods have been used to predict the location of fishing grounds. These include habitat suitability index (HSI), which is generally used to describe the quality of fish habitat, but recently has been applied to predict the location of fishing grounds. HSI models can be also used to inform fishery management and fish conservation. In this study, a HSI model was developed to predict the locations of T. albacares fishing grounds in the eastern Pacific using sea surface temperature (SST) and sea surface height (SSH) as explanatory environmental variables. The suitable ranges of SST and SSH were estimated using the frequency analysis method. Catch data for T. albacares were used as a suitability index, and quarterly suitability curves based on SST and SSH were derived using non-linear regression. Catch data were obtained from the Chinese longline fishery operating in the eastern Pacific Ocean (20°N-30°S and 85°W-155°W) in 2011. The spatial resolution of catch and environmental data is 1 degree latitude by 1 degree longitude, and data were recorded monthly. The HSI model was set up using an arithmetic mean model (AMM). The model was validated using separate a data set (2012 catch data from the same area). The T. albacares fishing grounds were mainly located in the waters with SST 24-29°C and SSH 0.3-0.7 m. The suitability index model for each factor (SST and SSH) was significant (P < 0.05). The accuracy with which fishing grounds were predicted for each quarter in 2012 varied from 60% to 71%, with an average of 66%. The actual T. albacares fishing grounds were almost all located in the forecast areas in all months. The HIS forecasting model developed in this study could provide valuable information for finding T. albacares fishing grounds in the eastern Pacific Ocean. However, in order to better forecast T. albacares fishing grounds using HIS models, more environmental factors should be included in the model, such as water temperature structure, sea front, Chlorophyll-a, and El Niño-Southern Oscillation (ENSO) index.