The accident happened at the front of Muang Thai Leasing Office in Chao-fah East Road.
Rescue workers arrived to find the woman sitting on the drain lid with her right leg firmly stuck in it.
They had to smash out some of the surrounding concrete to pull her leg out.
The woman, who refused to reveal her name, was taken to Vachira Hospital with minor injuries.
A Kusoldharm Foundation volunteer says pedestrians needed to take care while walking around Phuket as many footpaths had holes and other obstacles.