Diesel exports jumped 53% to 1.91 million tons, data from the Chinese customs authority showed, outpacing the previous record of 1.78 million set in December, Reuters reported.
Gasoline exports rose 25% in March compared with the same month a year earlier to 840,000 tons, but were down 21% from February.
Kerosene shipments abroad were 1.25 million tons, up 21.4% year-on-year and up 23% from February.
The high monthly shipments led to big increases in the first quarter and will reinforce concerns that China, one of the world's top energy markets, is contributing to a fuel overhang as refiners churn out more products like gasoline and diesel than the market can absorb.
China became a net exporter of fuel products in late 2016.
LNG imports totaled 1.99 million tons in the month, up 18% year-on-year but down 19.5% from February and the lowest monthly total since October last year.
That may reflect waning demand as temperatures rise, reducing the need for the fuel for heating.