I make a project and I think WSN module and gateway are a good solution for it, but I'm not sure about distance (its over 300 meters). Can I use directional antennas with WSN modules to increase transmission distance?
That might work - that's not a supported use and it hasn't been tested so I can't say for sure. WSN nodes are designed to be able to also be used in a router mode, allowing you to extend your network to up to 900 meters out (using 3 nodes, with 2 being used as routers). Designing your network with this in mind is probably the best approach. Take a look at the white paper linked below; it might be helpful for you during your planning stages.
you cannot cover the distance of 900metres what i think using WSN devices with using 2 routers. its written that only in line of sight it can communicate upto 300 metres (americas) and also theenvironmental conditions effects.