The 26-year-old man is accused of convincing 57 girls aged between ten and 15 to send him explicit photos of themselves or to undress for him in front of a webcam.
"The allegation is based on around 60 witness accounts but the police has proof that around 200 young girls were contacted," said prosecutor Pontus Melander.
The 26-year-old who has pleaded not guilty, risks six years in prison.
The Swede is alleged to have contacted his victims on the popular Dayviews website, where users share their photos.
Police tracked the man down by tracing his IP address and then raided his house in the beginning of February. Officers then found a large number of pornographic images and films in his mobile phone and on his computer.
According to the police, the man has had extensive contact with several young girls, some as young as between 10 and 13 years of age, and all from different parts of Sweden.
His behaviour and messages to young girls using the site aimed to "infringe the sexual integrity of the plaintiffs," said the indictment.
Several of the girls have since had to see a psychologist, said their lawyer Paola Negrete.
Witness accounts have been recorded on video and will be broadcast during the trial, said Melander, which will take place as a closed session. Four of the older girls are expected to testify in person.
The 26-year-old man, who is in detention pending trial, is also accused of hoarding child pornography.
Computers and a mobile telephone belonging to the Swede contained "a lot of images and many child pornography films," said a statement from the prosecutor.
The crimes were reportedly committed in Uppsala between 2009 and 2012.
The trial is expected to last 20 days.