I assume that you are asking how many justices voted each way in this case. If so, the answer is that the decision was made by a vote of 7 to 1. One justice abstained.
In this case, the Supreme Court ruled that racial segregation in public facilities such as train cars did not violate the 13th or 14th Amendments to the Constitution. It held that, so long as the facilities made available to both races were similar, they were constitutional. This is the origin of the idea of “separate but equal.” The Court held that requiring whites and blacks to sit apart was not specifically intended as a statement that whites were better than blacks. They held that such an interpretation of the law was purely something made up by people who wanted to interpret the law in that way.
In dissent was Justice John Marshall Harlan. Harlan’s dissent in Plessy is one of the most important in the history of the Supreme Court. This is where he argued that the Constitution should be color-blind and that the decision would allow states to strip away black rights. He was, of course, correct.
There was one justice who did not hear the case and did not vote on it. This was Justice David Brewer, who had to leave Washington on the day before the case was heard because his young daughter had died of tuberculosis in Texas.
The vote, then, was 7 to 1.