American companies are now allowed to lend money to Cuban entrepreneurs and to invest in infrastructure projects.
The new measures also make it easier for US studios to shoot films in Cuba.
The two countries restored relations last year, putting an end to more than five decades of enmity.
President Obama has urged Congress to lift a Cold War-era embargo that bans most trade between US companies and the communist-run island.
Congress has ignored his pleas, but over the past year the US government has announced several measures to encourage trade and a normalisation of relations between the two old foes.
The latest measures were announced by the US Commerce Department on Tuesday and came into force on Wednesday.
The key difference between this announcement and earlier efforts to ease trade with Cuba by the Obama administration is that this time the new rules will apply to trade with Cuban government agencies.
Previous steps were solely aimed at strengthening private entrepreneurs on the island, explains the BBC's Will Grant in Havana.
The easing of export restrictions will apply on a case-by-case basis in areas which "directly benefit the Cuban people," said Commerce Secretary Penny Pritzker.
She cited "disaster preparedness, education, agricultural production, food processing and public transportation".
The measures also lift further restrictions on Americans travelling to Cuba, making the current ban on tourism more difficult to enforce.
The embargo has been in place since 1960 and remains a contentious issue in relations between Cuba and the US.
President Raul Castro said at the UN General Assembly in September that now that diplomatic ties were back in place, the overall normalisation of relations "will only be achieved with the end of the economic, commercial and financial blockade against Cuba".
The United States has eased a number of trade restrictions with Cuba, in President Barack Obama's latest attempt to bypass the US Congress's economic embargo on the island.