The company, also known as ChemChina, said the strategic investment in Geneva-based Mercuria Energy Trading would expand its portfolio, according to a statement posted on its website.
Last week, ChemChina said it would buy Germany's KraussMaffei Group, which makes machinery for producing plastics and rubber, for €925 million ($1 billion).
"Through the investment in Mercuria Energy Trading, which has grown rapidly over the last decade, ChemChina will expand further into the energy sector," ChemChina Chairman Ren Jianxin said in the statement.
Mercuria, set up 2004, is one of the largest integrated energy and commodity trading companies in the world, according to its website with turnover of $106 billion in 2014.
The Swiss firm has 38 offices in 27 countries.
"An investment by ChemChina in our company reaffirms Mercuria's business model as well as growth potential," Marco Dunand, chief executive officer of Mercuria Energy Group, said in a separate statement.
Neither company disclosed financial terms.
ChemChina is one of more than 100 major state-owned Chinese enterprises which reports directly to the central government.
Last year, it announced the acquisition of Italian tyremaker Pirelli in a €7.4-billion deal.
Beijing encourages the country's companies to invest abroad to secure raw materials and expand into foreign markets.
Last week, China's Haier Group unveiled a deal to buy the appliances business of US industrial giant General Electric for $5.4 billion.
In another deal announced last week, Wanda Group — founded by China's richest man Wang Jianlin — acquired Hollywood studio Legendary Entertainment for $3.5 billion.