No more than six months. According to "How long does it take for state-owned enterprises to become full members" published by QueryPro.com, the probation period of state-owned enterprises is of course determined according to the provisions of China's labor law. If the term of the labor contract is more than three months but less than one year, the probation period shall not exceed one month. If the term of the labor contract is more than one year but less than three years, the probation period of enterprises and institutions shall not exceed two months. If the labor contract is more than three years, the probation period shall not exceed one month. If the employer fails to sign a labor contract with the employee at the beginning of employment, it first violates the provisions of the Labor Law. The three-month probation period should be included in the contract term, not independent of the contract term. The so-called "regularization" after the probation period is actually an attempt to escape the obligation of probation. In fact, since the day when the laborer entered the company, the two sides have formed a factual labor relationship. According to the relevant regulations of Shanghai, there is no probation period under the factual labor relationship. Therefore, if the salary during the probation period is lower than that of other employees in the same position, the difference will be made up.