How to control a dog who is intimidated by big dogs?

You can slowly integrate the dog to others. Find somebody who you know that lives close to you and has a dog (let's call it Spot) so that you can go around to introduce it. However do not stick them in a room and expect it to be okay. You must keep your dog shut in one room and excite him. Play with him and make sure the other dog is excited too. If all goes well they should bark. Your dog might not like this at first but soon enough it will become apathetic to the barking (when excited). When you dog is okay with the barking then it should not be as startled when the next stage is introduced. Take the dogs out for walks. Put your dog behind 'Spot' with at least 10 metres of space. Do this frequently for 5 minutes a time. Keep doing this and reduce the space between the dogs. (You will want to get your dog used to the smell of 'Spot' so get an old sheet and rub 'Spot' with it until it smells strongly. Leave the blanket where your dog usually sleeps - in it's bed preferably - and it will get used to the smell of dogs.) Once your dog is more comfortable with this dog put it in the same room as 'Spot' and keep them together for several hours. Again do this regularly and soon enough your dog will be okay with the smell, look and noises dogs make. Make sure your dog is introduced to other dogs on a lead before you put them together, otherwise it could end up with fighting, depending on how docile/vicious you dog is.