Due to the knock limitations, the compression ratio of hydrogen engines is generally lower than that of diesel engines. Overcoming the knock combustion constraints under high compression ratios is hence essential for the application of hydrogen engines. The numerical simulation was employed to investigate the potential of injection strategies combined with ignition timing to suppress knock in a direct-injection hydrogen engine under high compression ratio conditions.The results indicate that the knock intensity (KI) first decreases and then increases with rising injection pressure at a compression ratio of 15. The minimum KI occurs at an injection pressure of 6 MPa, where hydrogen distribution near the spark plug becomes more concentrated, promoting easier mixture ignition and the mixture forming a more stable flame kernel. The variation of knock intensity with injection timing is nonlinear. At －100°ATDC, the in-cylinder mixture distribution becomes more homogeneous, the combustion phasing (CA50) moves closer to top dead center (TDC), and KI reaches its lowest value. However, the lowest achievable KI values obtained by adjusting either injection pressure or injection timing alone still exceed 1 MPa. Therefore, delaying the ignition advance timing is necessary to further mitigate knock.