I add this method in GB2ShapeCache-x.cpp. Because it don't think a sprite scale.

GB2ShapeCache-x.cpp

void GB2ShapeCache::addFixturesToBodyForSprite(b2Body *body, const std::string &shape, CCSprite *sprite) {
    std::map<std::string, BodyDef *>::iterator pos = shapeObjects.find(shape);
 
    BodyDef *so = (*pos).second;
    FixtureDef *fix = so->fixtures;
    if ((sprite->getScaleX() == 1.0f) && (sprite->getScaleY() == 1.0f)) {
        // simple case - so do not waste any energy on this
        while(fix) {
            body->CreateFixture(&fix->fixture);
            fix = fix->next;
        }
    } else {
        b2Vec2 vertices[b2_maxPolygonVertices];
        while(fix) {
            // make local copy of the fixture def
            b2FixtureDef fix2 = fix->fixture;
 
            // get the shape
            const b2Shape *s = fix2.shape;
 
            // clone & scale polygon
            const b2PolygonShape *p = dynamic_cast<const b2PolygonShape*>(s);
            if(p)
            {
                b2PolygonShape p2;
                for(int i=0; i<p->m_vertexCount; i++)
                {
                    vertices[i].x = p->m_vertices[i].x * sprite->getScaleX();
                    vertices[i].y = p->m_vertices[i].y * sprite->getScaleY();
                }
                p2.Set(vertices, p->m_vertexCount);
                fix2.shape = &p2;
            }
 
            // clone & scale circle
            const b2CircleShape *c = dynamic_cast<const b2CircleShape *>(s);
            if(c) {
                b2CircleShape c2;
                c2.m_radius = c->m_radius * sprite->getScale();
                c2.m_p.x = c->m_p.x * sprite->getScaleX();
                c2.m_p.y = c->m_p.y * sprite->getScaleY();
                fix2.shape = &c2;
            }
 
            // add to body
            body->CreateFixture(&fix2);
            fix = fix->next;
        }    
    }    
}