Thank @Alexander Vasilyev. I understood my problem as you said. I want to explain a litte more here. In fact, the object "params" is the object configuration the table ng-table, then if "params" changed (ex: count or a property of the object), ng-table will invoke function getData() to refresh table.
In my case, I want to get information in the object "params" and change it but I dont want to refresh ng-table. I did it by cloning object "params" et work his object copied. Clone the object in JS with jQuery :
var resultParams = jQuery.extend(true, {}, params.$params);
And then, I will work on the object resultParams instead of "params" original.