Can a labor service company buy a construction company? Is it legal?

Yes, it's not illegal. According to the company law, labor service companies can buy construction companies. Labor service company is an enterprise form that provides labor service. Establish labor cooperation relations with employers and provide them with various labor resources, including hiring short-term, temporary and contract workers. The main business of the labor service company is to match the appropriate labor force for the demander and provide the labor force with benefits such as wages and social insurance.