Satisfaction with the number of staff on trains, ticket machines and stations were points identified in the latest National Rail Passenger Survey (NRPS).
But less than two thirds of passengers who took part think they are getting value for money.
ScotRail said the 90 per cent satisfied or very satisfied response was 3 per cent up on last year.
It is the first survey since Abellio took over the ScotRail franchise on April 1 last year.
The operator said it will continue to work to make improvements with faster and bigger trains.
Phil Verster, managing director of the ScotRail Alliance, said: “When people think about the railway, it’s often about the trains and the track. As important as these are, the reality is that the railway is only as good as the people who make it work.
“These figures show that we are incredibly fortunate here in Scotland to have thousands of people who work on our trains, in our stations and in our depots who are so obviously dedicated to delivering a good service for our customers.
“We are absolutely determined to give the people of Scotland a railway that they can be proud of. To do this, we cannot sit back and relax for a moment. So, while this rise in customer satisfaction is great news it only drives us to work even harder.
“Over the next couple of years we are delivering ScotRail’s biggest ever train improvement programme and new faster, longer, greener trains will be introduced in 2017.”
NRPS chief executive Anthony Smith said: “Passengers are in broad agreement that ScotRail is doing a good job, but there is still room for improvement.
“Less than two thirds of passengers think they’re getting value for money and only around half think that their train company deals well with delays.
“ScotRail and Network Rail should listen to customer views, both positive and negative, and strive for even better results.”