China Life Insurance Company Limited is a subsidiary of China Life Insurance (Group) Company.
Three insurance companies are different. In fact, China PICC and China Life were originally the same company, and its predecessor was China People's Insurance Company.
But now, they are two independent insurance companies with different business scope and services.
If you want specific information, you can read this article: What is the relationship between PICC China and life insurance? Whose strength is more stealing the mirror?