The charges against the officials include misuse of public funds, disobedience and breach of confidence, Catalonia's high court said in a statement.
The 30 officials are one step away from trial, but still have the possibility to appeal the decision.
Among the accused are former members of the government of Catalonia's ex-president Carles Puigdemont and the directors of regional television channel TV3 and Catalan public radio Catalunya Radio.
The judge has set bail for 17 of those charged with misuse of public funds at €5.8 million ($6.5 million) which is what she estimates was spent on the referendum, the statement read.
Twelve Catalan separatist leaders are on trial in Madrid over their role in the banned referendum that took place on October 1, 2017, and the short-lived declaration of independence that followed weeks later.
Nine of these were regional ministers at the time, two are civil society leaders and the last defendant is the former Catalan parliament speaker.
The charges against them include rebellion, which carries up to 25 years in jail.
In parallel to this closely watched, divisive case, the high court in Barcelona had since March 2017 been investigating the role of other less high-profile officials in the referendum.
The investigating judge accuses the 30 officials of “organising a series of actions that made sure” the illegal referendum went ahead, “committing public budget for this,” the statement read.