The Solomon Islands now has an operating embassy in Beijing. Prime Minister Manasseh Sogavare officially opened it last week.
The police cooperation pact was among nine deals Sogavare signed when he met with Chinese Premier Li Qiang.
He also met China's President Xi Jinping. The two agreed to establish a strategic partnership, according to Chinese state television.
Sogavare was on his first visit to China since both countries signed a security pact last year, causing concern from the United States and neighbors, including Australia.
The Solomon Islands switched diplomatic ties from Taiwan to Beijing when Sogavare came to power in 2019. Beijing claims the democratic nation of Taiwan as part of its own territory.
China will continue to provide assistance to the Solomon Islands to enhance its law enforcement capacity, according to a joint statement released by China's official news agency.
Reuters reportsChinese telecom giant Huawei is already building a $66 million cellular network in the Solomon Islands. A Chinese state company will also redevelop the port in the capital of Honiara.
The two countries also reached agreements in civil aviation, trade, economy, technology and sports.
Honiara is hosting the Pacific Games in November, and China has constructed the stadium.
