Crystal Palace forward Howat opened the scoring - and her Scotland account - on the 11th minute with a delightful, lofted finish into the far corner from the right of the box.
The 28-year-old then turned provider for strike partner Hanson to bury a quickfire second at Estadio Municipal de Chapin.
And by minute 15, it was 3-0 when Howat looked up and caught goalkeeper Zhu Yu off her line with an outrageous, long-range drive.
China were thrashed 8-0 by England last week and appeared destined for another heavy loss but they pulled one back when Zhang Linyan was afforded too much space in the box to finish.
The world's 16th-ranked nation then made the Scots suffer for spells towards the end of the first half.
Scotland withstood that pressure and passed up the chance to go 4-1 up after the break when a trip on Cuthbert presented Howat with the opportunity to complete a hat-trick.
The forward was left disappointed, though, when she struck the left-hand post before lifting the rebound over the crossbar.
A header into the bottom corner from Zhang Rui then made it a nervy finish for Scotland, with Huo Yuexin narrowly missing on the slide soon after.
But Andreatta's side held on to go into next year's World Cup qualifying campaign on the back of a hard-fought success.