你可以使用remote.message事件从页面接收所有的console.log()，然后使用PhantomJS的fs模块（fs.write()）将它们写入一个文件。

var fs = require('fs');
casper.on("remote.message", function(msg){
    fs.write("file", msg+"\n", "a");
});
...

//Keep a reference to the original function
var original = console.log;

//Override the function
console.log = function(arg) {

   //Do what you want with the arguments of the function
   ....

  //Call the original function
  original.call(this, arguments);
}