Google Inc. has bet tens of millions of dollars on a Chinese search-and-smartwatch company that marks a rare deal in China and renewed interest in a market it mostly exited in 2010.

Google GOOGL, -1.61% GOOG, -1.50%  said Tuesday that it invested in Mobvoi Inc., a Beijing-based artificial-intelligence startup that provides mobile voice search in Chinese. The company has developed a Chinese voice search mobile app with two million accumulated users, a Chinese smartwatch operating system and a smartwatch called Ticwear.

Terms weren’t disclosed. Based on previously disclosed investments in Mobvoi, the amount of Google’s investment is likely to be in the range of $40 million to $45 million. Google and Mobvoi said only that Mobvoi received $75 million in investment since 2012.

Alphabet Inc. Cl AMar 15May 15Jul 15Sep 15Nov 15Jan 16Source: MarketWatch

Mobvoi, founded by Google alumnus Li Zhifei, has posted sales of 30,000 of its smartwatches since the timepieces were launched June. It became the voice-search and speech-recognition provider in China for the wearables version of Google’s Android mobile operating software around that time.

Past investors in Mobvoi included Sequoia Capital China, ZhenFund and SIG.

An expanded version of this report appears at WSJ.com.