Laser directed energy deposition provides a flexible, fast, and agile processing for high-entropy alloys. Reasonable single-pass process parameters are the key to ensure processing. In order to study the influence of process parameters on the deposition morphology of FeCoCrNi high-entropy alloy in the laser directed energy deposition process, response surface methodology was used. The influence of laser power, powder feeding rate, and scanning rate on the dilution rate and aspect ratio was studied. Prediction models of dilution ratio and aspect ratio were established. The results show that the dilution rate and aspect ratio are negatively correlated with powder feeding rate, and positively correlated with laser power and scanning rate. The experimental results indicate that the prediction errors of dilution ratio and aspect ratio are 2.29% and 4.45% respectively, and the established models are in good agreement with experiments.