China's three major telecommunications operators refer to three domestic companies that provide communication services for fixed telephones, mobile phones and Internet access, namely China Mobile, China Telecom and China Unicom.

China Unicom:

China United Network Communications Group Co., Ltd. ("China Unicom") was formed on the basis of the merger of the former China Netcom and the former China Unicom on January 6, 2009. It has branches in many countries and regions outside of China. It is the only telecom operator in China listed in New York, Hong Kong and Shanghai at the same time. The establishment of China Unicom introduced competition in China's basic telecommunications business, and played a positive role in promoting the reform and development of China's telecommunications industry.

China Mobile:
China Mobile Communications Corporation, established on April 20, 2000, is a mobile communications operator based on GSM, TD-SCDMA and TD-LTE networks. A state-owned enterprise is directly controlled by the Chinese government of the People's Republic, which is also a company listed on the New York Stock Exchange and the Hong Kong Stock Exchange. China Mobile-dominated China Mobile services have been established since its establishment. As of 2010, China Mobile controlled the vast majority of its domestic mobile services market, with a market share of 70%. China Unicom and China Telecom own 20% and 10% shares, respectively.
China Telecom:
China Telecom Corporation is a large state-owned telecommunications company in China and a global partner of the Shanghai World Expo. It has been selected as a "World Top 500 Enterprise" for many years. It mainly operates integrated information services such as fixed telephones, mobile communications, satellite communications, Internet access and applications.
China Telecom Corporation has 21 provincial enterprises. The group company and 21 provincial-level enterprises are parent-subsidiary relationships that use capital as a link, and network and business as a link. The establishment of China Telecom Corporation marks that China's telecommunications industry has entered a new stage of healthy development.

After more than 20 years of long-term development, China's communications industry has gradually formed a situation of 2G / 3G / 4G coexistence. Mobile phone communication signals are transmitted through a certain frequency, and the frequencies and network standards of the three major operators are not The same, this causes the same mobile phone may not be universal among the three major operators. We often encounter mobile phones bought at China Unicom or China Mobile, and the telecommunications card cannot be used. This is the case. Understand the frequency bands and network standards owned by the three major operators, sort out the data, you can see at a glance through the following table: