Children with autism and anxiety go together hand in in hand, or hand in glove like my title suggests. If your child is dealing with autism then one of their symptoms is anxiety, plain and simple. They have problems communicating with and understanding the world around them, and this creates anxiety. Children with autism will often act out (sometimes aggressively) over what seem like fun events. This stems from the anxiety they feel from the event invading their life.
Changes in routine can be a HUGE source of anxiety in children with autism. What seems like a fun outing to a birthday party could end up in a major meltdown if not done properly. Lets say for instance you know that your child with autism will be attending a birthday party over the weekend. Early in the week you may want to start showing them pictures of parties, cakes, kids playing games. If you have pictures of the people that will be attending, show them those too. This will help them prepare for what they are going to be doing, thus relieving some of their anxiety, and setting them up for success.
If you need to make what will be perceived to be a negative change to your child with autism's daily routine, here is a way you can go about it. Start of just introducing them to the idea of change. Tell them "tonight instead of homework you can play video games instead, but just for tonight". This will show them that change does not always have to be bad, sometimes it can be good. Next try a change that is really of no consequence. Maybe have them do their homework at six instead of seven, before dinner instead of after dinner. A change that is just that, a change. Lastly move into the "negative" change. Change one of their designated free or play times into a chore time. This gradually eases them into the idea of change, reducing anxiety along the way.
For overall long term anxiety unfortunately medication is sometimes required. The doctor will most likely prescribe children with autism a selective serotonin re-uptake inhibitor (SSRI). These are drugs like Proozac or Zoloft.
Every child with autism is as different as every other child so there is no one size fits all answer. YOU know your child best. If you do go the medication route be sure to monitor your child closely for side effects. There are many natural methods you can try prior to actually using medication.