A horse that’s hard to catch is usually trying to exhibit his dominance over you. In terms of the social language of horses, there are basically two options: stay here or go away. Horses will make gestures to each other that say one of these things or the other, and the “target” of this will then respond by doing one action or the other. When a horse is hard to catch, he is essentially telling you that he wants you to go away and that he can make you stay away from him if he wants to.
One of the first steps in getting hold of a horse that’s hard to catch is actually going out of your way not to catch him. While your horse is at pasture, go join him. Walk around the pasture, paying little or no attention to him. If he approaches you, walk away from him. Make it clear to the horse that you are in charge and that you decide what interactions will take place and when. Doing this for short periods of time a few times a day is usually more effective than one longer visit. After several days of this, you can initiate contact with your horse. Do not try to catch him right away. Instead, plant the seed that sometime when you approach him it is simply to greet him, scratch him, have a little visit. If your horse seems intimidated by the fact that you are carrying a lead rope and halter, try draping them over your shoulder in a more casual stance.
If you try this and find your horse is still hard to catch, you may need to 
work with your horse in a small paddock. Keep the horse moving, by using a longe whip to get him to continue moving forward. For the first several minutes the horse will probably think this is fun. When he starts to slow down, however, keep him moving. After a few minutes, instruct your horse to halt, consistently using whatever command you choose to use. When he stops, praise him and then get him moving again. Obviously the point is not to exhaust your horse, but rather to remind him that you are the decision-maker. When he consistently stops on command, try approaching him. If he allows you to do so, praise him and scratch him for a moment then send him on his way again. Repeat this process over and over until the horse is accustomed to standing while you approach him every time. At this point, you can try to halter him. If the horse is still hard to catch, back up a few steps and begin this process again. Consistency and praise are the keys.
A horse that’s hard to catch is simply seeking direction. He needs clarification that you are in charge in this relationship. Once you establish yourself as the leader, you will no longer have a horse that’s hard to catch.
