Legal analysis: illegal. The training period is also the duration of labor relations. Laborers' participation in the training arranged by the unit is regarded as providing labor and normal work for the unit. The unit shall pay the wages of the workers during the training period according to the wage standard agreed in the labor contract. The salary during the training period shall not be lower than the local minimum wage.

Legal basis: Article 10 of the Labor Contract Law of People's Republic of China (PRC) establishes labor relations, and a written labor contract shall be concluded. If a labor relationship has been established and a written labor contract has not been concluded at the same time, a written labor contract shall be concluded within one month from the date of employment. If the employer and the employee conclude a labor contract before employment, the labor relationship shall be established from the date of employment.