It is very important to determine the protonation constants of tetraphenylporphyrin derivatives for studying their colorful performance. The over-all protonation constants of two tetraphenylporphyrin derivatives were determined by spectrophotometric methods. The influence of electron effect and steric hindrance of substituting group on overall protonation constants was discussed. With chromophore introduced, it is expected to enhance the selectivity of tetraphenylporphyrin derivatives reagents.