Abstract: In order to stimulate and encourage consumer spending，business operators may directly or indirectly introduce their products or services.Such words are commercial speeches.Commercial speeches are protected by the constitutional freedom of speech，and enjoy the same legal status with political opinions.For the sake of public interest，government can put a restriction on commercial speech.But according to fourpart analysis developed and applied by the Supreme Court of the United States in Central Hudson Gas & Electric Corp.v.Public Service Commission case in 1980，commercial speech can be protected by law only when it concerns lawful activity and not be misleading，and when the restriction serves and directly advances government interest and the restriction is not more extensive than is necessary to serve the interest.The fourstep analysis is of reference value to judicial practice concerning the protection and restriction of commercial speech in China.

Key words: commercial speech, freedom of speech, constitution, commodity, service, false advertising