摘要：The practice of four-character Chinese idioms alteration used in the signboards by substituting character （s） with their homophonous words has grown into a general trend. Fifty-one altered idioms are collected. The majority of the modifiers are medium-small store owners. idiom alteration for specific purpose differs from the idiom misinterpretation. Speedy economic growth and material wealth pursuit social context stimulate the idiom alteration behavior which enforces the pragmatism value orientation. By modifying idioms into four-character structures of strong practical effect, the obvious pragamtic value of the businessmen and of Chinese are manifested. A causal analysis method is used.