Hi, thak you for your answer , it tried related field before and its didn't worked , and it now that I noticed that i didn't had FB field in xml, it was in comment ( just in python) hhhhhhhh, and now its work . 

Thank you again 

use Environment for that like this,

module MA->class CA

class ClassA(models.Model):

    _name = 'modulea.classa'

    fielda = fields.Char('Name', required=True,)

module MB->class CB

class ClassB(models.Model):

    _name = 'moduleb.classb'

    fieldb = fields.Char('Name', required=True,)

    def get_recordes(self):

        for record in self.env['modulea.classa']:

            print record.fielda

I hope this works.