my visa has M, my companion's 02. we are visiting Hong Kong,Shanghai,Qingdao,Nanjing,Xiamen.

If you are on a cruise and will visit the ports of Hong Kong, Shanghai, Qingdao, Nanjing and Xiamen, a multiple entry visa will be required. Your visa is ok for the trip.

Your companion's visa is not ok, you can only visit 2 ports in Mainland China, if you are both U.S. citizen, a visa is not required for HongKong, you just need the visa for Mainland China ( Shanghai, Qingdao, Nanjing and Xiamen).

Now, it is almost impossible for him/her to apply for a new multiple entry visa. When he/she visits the last two ports within Mainland China, she can try to apply for disembarkation permit, then he/she can go to the city.