I dont know how it works in maxthon but if anytime in future you make the switch to firefox the below method should work.Oh btw no plugins required.
Right click on the page which has the flash animation.
View Page info.
Media.
Locate the .swf file there & click "save as".
This is a boon when there are multiple flash files on a single page which you would like to save.
Info Courtesy Neowin.