His speech at the Boao Forum for Asia - often referred to as Asia's Davos - appears to be an attempt to calm a trade row with the US.
He pledged to cut import tariffs on cars and relax requirements for foreign firms investing in China.
But there were few specifics on when the changes would happen.
Chinese investment in US falls sharply
Analysis: Why China won't baulk at US tariff threat
'Zero-sum game'
Mr Xi made no specific references to the ongoing spat with the Washington which has seen both sides announce tit-for-tat plans to slap tariffs on imports.
But in a veiled swipe at US President Donald Trump's America First stance, Mr Xi called for openness.
"Human society is facing a major choice to open or close, to go forward or backward," Mr Xi said to the audience made up mainly of Chinese and international investors.
"In today's world, the trend of peace and cooperation is moving forward and a Cold War mentality and zero-sum game thinking are outdated.
"Paying attention only to one's own community without thinking of others can only lead into a wall. And we can only achieve win-win results by insisting on peaceful development and working together."
President Trump, whose plan to hit hundreds of Chinese products with duties have stoked fears of a trade war, has yet to react.
Washington claims China has failed to fulfil earlier promises to open up the economy - including putting up barriers to international companies accessing markets and forcing investors to form joint ventures and hand over intellectual property.
More about: XiJinping
-1731503623.jpg&h=190&w=280&zc=1&q=100)
