Okay, Spider Man may have super strength and stuff like that, but he is not match to an alien with invisibility, a death laser gun, and entire arsenal that fits onto a suit, and claw hands. Not to mention, Spider Man is a teenage nerd, omeone who can barely grasp the concept of talking to women without stuttering like a lunatic. If he can beat a Predator, then a group of soldiers in vietnam armed to the teeth should be able to take out a predator without any casualties. Spider man has spider sense, sure, but that's for stuff like someone about to punch them. A bullet- or rather a laser- would move way to fast for him to be able to dodge it. Predator wins this fight any day of the shark week.
Actually he is able to dodge things at say the rate of a bullet. In the first spiderman movie you see him do matrix like moves to dodge everything the Green Goblin had for him. That includes pumpkin bombs and his glider. Predator does not have "claw hands" he has a device that has claws. Predators cloaking device would be no use here because Spidey would know he was going to hit him every single time.
Spider man has a major downfall that brings him to a sever disadvantage - non lethality. Now I don't read comics so I'm mainly going off the movies here, but he never really kills anybody. In Spider Man, he dodges a hoverboard and it impales Green Goblin. In Spider Man 2 Doc Ock kills himself because he turns good. In Spider Man 3, he thinks he kills Sandman but didn't, Venom kills Harry, and Eddie Brock is an idiot and kills himself. Predator is a killing machine with no hesitation, while Spider-Man is a teenager who can't kills anyone for any reason. Even if Spider Man did catch a Predator in his web, it wouldn't stop it. It has claws coming out of it's arms, it can get out of webbing. Every other foe of Spider Man could.
Here's another one, the kicker: Spider-Man is an open combat fighter. It has been proven throughout the predator series that the only real way to fight a predator and not be obliterated is to cover yourself in mud and hide. Spider-man can't hide & fight, he's not a stealthy person. Predators have like a x2 spider sense, where they can detect heat signatures from anywhere. Sure, his spider sense could help him dodge one or two lasers, but try tons of lasers coupled with missiles and spike launchers.
Predators are basically unbeatable. Superman could beat one, but only because he's superman.
Predators are the ultimate killing machines. Almost nothing can kill them. In Predator, the human doesn't even kill him. he blows himself up using his bomb. In Predators, all the predators die by either explosions which kill the person who caused it, and other predators. (AvP doesn't count as myhtos) Spider Man has enough trouble with Green Goblin, The Lizard, and Doc Ock. All of which could be easily defeated by a predator. We even saw the outcome of a predator coming to an urban area in Predator 2, in which he caused some serious damage.
Predator could beat pretty much any superhero in a fight, Spider Man is certainly no exception.