Started a book many years ago about a planet with dinosaurs and Stone Age man on it. Earth colonists had arrived and used some sort of mind control technology on the dinosaurs. Also introduced some Stone Age natives in the intro/first chapter. Never got to finish the book and really want to.
Not sure how long "many years ago" is. But, this sounds a lot like the S.M. Stirling novel The Sky People. It is the first of the Lords of Creation Series.
Points that match:
...about a planet with dinosaurs and Stone Age man on it.
Check: In this alternate universe, life exists on Venus and Mars. In 1962 the USSR drops planetary probes on Venus and discovers people, both humans and Neanderthals, on the planet.
Earth colonists had arrived
Check: Crewed flights by the Soviets and later by the Americans establish bases on the planet (the American one named Jamestown; the Soviet one Cosmograd)
...and used some sort of mind control technology o the dinosaurs.
Check: The new arrivals are somewhat taken back by the ceratopsia used as a shuttle bus. The dinosaur has been “iced” by the insertion of an Internal Control Device into its brain, which allows the creature to be controlled with messages sent directly to the brain.
Also introduced some Stone Age natives in the intro/first chapter.
Check: Although the base doesn't have any means to check DNA (as in this alternate timeline, the majority of research funding has been spent on space travel), other tests indicate that the natives are closely related to Terrans. The fossil record is very spotty, with occasional infusions of new species, but no one has an explanation as to why there are humans and other Earth animals and plants on Venus.
Cover looks like:
It might be Dinosaur Planet by Anne McCaffrey. Published in 1978.
Definitely has colonisation of a planet with dinosaurs, I can't remember if it has cavemen.