In this paper,a label free C-reactive protein（CRP）photoelectricimmunosensor was constructed using porous porphyrin compound-Au nanoparticles（Au NPs@PAF）as an immobilized substrate.Under the optimal conditions,the CRP was quantitatively detected by chronograph current method.There was a good linear relationship for the sensor versus photocurrent in the range of 0.05-60 ng/mL,with a linear correlation coefficient of 0.994 6.The limit of detection was 0.017 ng/mL,and the average recovery was 102%.This sensor provided a sensitive method for the detection of C-reactive protein with good selectivity.