Telecom signals will cover all sections of the Beijing subway before the August Olympics, a company spokesman said.
The capital currently has five subway lines with 140 km of track, moving millions of passengers daily. However, lines one and two, which were put into use decades ago, were not originally equipped with telecom systems.
To update the service, a renovation project was started on August 31 last year and was scheduled to be completed as of mid July, spokesman Jia Peng told the Beijing-based Star Daily newspaper.
The equipment had been installed and negotiations would soon start with individual mobile service providers, he was quoted on Wednesday as saying.
Beijing plans to add three new subway lines this year to expand the system to 200 km.
The Olympics will open on August 8.