The group, chaired by Hong Kong-based billionaire Joseph Lau, is said to have won a three-month auction with a bid near the asking price of £300m.
Moorfield Group and Gerald Ronson’s Heron were also in the running for the 600ft building, previously known as the Nat West Tower.
The sale is likely to also include five low-rise buildings surrounding the skyscraper, among them the Grade I listed Gibson banking hall.
The deal is the latest in a string of London property investments by foreign buyers. Last year the Chinese sovereign wealth fund joined Qatar to lead a large equity raising for Songbird, the majority shareholder in Canary Wharf.
Lau owns numerous properties in Hong Kong and entered the Sunday Times Rich List this year, with an estimated wealth of £3.8bn.
Tower 42 would be the first large property acquisition for Chinese Estates, though Lau himself spent an estimated £33m on a six-floor mansion in Belgravia in December.
Owners BlackStone and Hermes Real Estate put the skyscraper up for sale in April.
The building has several tenants whose leases are up for renewal in the next two years, giving a new owner the chance to raise rents in line with what many predict will be rising market prices.
Representatives from BlackRock, Hermes and sale adviser Jones Lang LaSalle refused to comment on the news yesterday. Chinese Estates Group was unavailable for comment.