The protesters had been blocked by police as they tried to march into the capital, Nay Pyi Taw, on Wednesday, resulting in scuffles.
They were demanding union recognition and for fired workers to be re-hired.
The new government has been discussing amending military-era laws allowing police to clamp down on such protests.
The workers had walked for three weeks in searing temperatures from the northern Sagaing Region, where around 100 workers had been fired from a timber factory.
Police Col Zaw Khin Aung said it was "okay to stage protests for their rights in their respective region but we can't afford to let them protest in Nay Pyi Taw area, which is a special area under the president".
A police officer said that 51 of the 71 protesters detained had been charged and taken to nearby Yaminthin Prison after they refused to be split up from their fellow demonstrators.
Regional police head Ko Ko Aung said "around 50" had been charged. He told AFP the authorities had banned the march on the grounds of national security.
Nay Pyi Taw was built and made the administrative capital 10 years ago by the Myanmar's former military rulers.
It is still considered a military stronghold, despite the National League for Democracy's victory at the last elections.
Around 50 factory workers and activists involved in a protest march in Myanmar (also known as Burma) have been charged with rioting, police said.