This paper describes the use of camera cell phone to detect the gold nanoparticle-labeled immunoassay results on microfluidic chip. On-chip heterogeneous immunoassay between anti-human IgG and human IgG (hIgG) was performed and the results were amplified by gold nanoparticle-enhanced silver staining to transform the nano-scale probe into detectable silver precipitation film. The detection results obtained by camera phone showed good correlation with the concentration of hIgG. This detection scheme is simple, low cost and easy to use and has significant promise for portable diagnosis and point of care testing on microfluidic platform.