Diffuse reflection spectra and their differences of normal human bladder and superficial human bladder cancer mucosa/submucosa tissues were studied in the spectral range from 300 nm to 900 nm in vitro. Diffuse reflection spectra of tissues were measured with a spectrophotometer with an integrating sphere attachment. The results of measurement show that diffuse reflection of normal bladder mucosa/submucosa tissue at each wavelength is obviously higher than that of superficial bladder cancer mucosa/submucosa tissue at the corresponding wavelength. The peaks in diffuse reflection spectra for normal bladder mucosa/submucosa tissues were 52.4% at 370 nm, 60.7% at 520 nm, 56.1% at 550 nm and 75.5% at 660 nm, respectively, while the peaks in diffuse reflection spectra for superficial bladder cancer mucosa/submucosa tissues were 43.7% at 320 nm, 33.4% at 520 nm, 30.6% at 550 nm and 70.2% at 660 nm, respectively. There was a peak in diffuse reflection spectra for normal bladder mucosa/submucosa tissues at 370 nm, and there was not a peak for superficial bladder cancer mucosa/submucosa tissues at 370 nm. There was a peak in diffuse reflection spectra for superficial bladder cancer mucosa/submucosa tissues at 320 nm, and there was not a peak for normal bladder mucosa/submucosa tissues at 320 nm. Pathological changes of bladder mucosa/submucosa tissues induce the decrease of the peak values in diffuse reflection spectra for tissues of 45.0% at 520 nm, 45.5% at 550 nm, and 7.02% at 660 nm. The results show that pathological changes of bladder mucosa/submucosa tissues induce changes in the component and structure of tissues, and especially quantitative changes in oxyhemoglobin and de-oxyhemoglobin of tissues obviously.