This paper presents a dual-injection strategy to achieve diesel partial homogeneous charge compression ignition (p-HCCI), which is the combination of HCCI-like combustion and traditional diesel combustion. The dual-injection strategy involves a negative valve overlap (NVO) fuel injection and a traditional fuel injection. The NVO injection occurs during the negative valve overlap period to prepare the homogeneous mixture for HCCI combustion. The traditional injection occurs at the end of the compression stroke to achieve diffused combustion. The results indicate that the NVO injection affects the combustion and emission characteristics in a different way compared to the traditional injection. The increase of NVO injection turns the combustion into HCCI-like combustion and advances the combustion phase. The increase of traditional injection makes the maximum heat release rate (HRR) higher. The emissions results indicate that p-HCCI can greatly reduce the NOx emissions compared to the baseline engine and maintain the same thermal efficiency. However, the NOx emissions increase with the increase of total injection. More traditional injection deteriorates the smoke emissions easily because of little time for fuel to mix with the intake air. The NVO injection ratio has been optimized at medium load according to the emissions and the thermal efficiency, and the optimum result is in the range of 30-40%, which can reduce the NOx emissions by about 40% and the smoke emissions by about 30%. However, the NVO injection should not be used at low load to stabilize the combustion.