In this research, a critical power correlation is proposed for tight lattice bundle system. The correlation is developed from searching the relationship between local heat flux and critical quality based on JAERI axially uniform heating and axially non-uniform heated data. The proposed correlation is fit for the condition that mass velocity G<2500 kg/m^2s, with exit pressure in the range from 3 MPa to 8.5 MPa. The developed correlation is verified with BAPL data, JAERI axially uniform heated data and JAERI axially non-uniform heated data with good accuracy. The correlation also predicts reasonable parametric trends of mass velocity, pressure, inlet temperature and radial peaking factor on critical power.